Problems adjusting full range FIP screw

[wwheeler]

I tried to adjust the full range screw on my FIP tonight with no luck after I read all of the info regarding the adjustment.

I removed the socket head cap screw and seal ring from between the two solenoids with a 5mm Allen wrench. I used a long thin slotted screwdriver to try to find the internal screw. When I inserted the screwdriver about 1", I ran into something that was lightly sprung. I could not find the slotted screw so I pushed about 3/4"deeper, I then ran into something that had a much higher spring rate. I still could not find a slot in the screw here either. If I had to guess, this last spring felt like it was moving the rack. 

Is there some special screwdriver that needs to be used? Why can't I find the adjustment screw? When I do find it, does it have the same feel (click) as the idle mixture knob?

Thank you! 

[jeffc280sl]

I'd say the first lightly sprung fitting you hit was the adjustment screw.  It is part of the rack so it will push forward if you apply pressure.  When you hit the screw, lightly apply pressure and turn the screw driver to seat the blade.  Yes the screw does have clicks like the idle adjuster.  If you still can't find it I suggest you remove the top solenoid.  You should be able to see the rack screw through the opening.

[wwheeler]

Thanks Jeff. It is reassuring having someone who has done this and is very knowledgeable about the FIP, guide you through it. I'll give it another shot.

[jeffc280sl]

My pleasure Wallace.  The slot in the adjusting screw is not very wide as indicated by the opening size.  However it is relatively thick.  The end of your screw driver does not need to be very thin in fact a little thicker is better.  Less slop when adjusting.  ASs you most likely know CW imeans less fuel volume and CCW is more.  Once you are comfortable with the screw I suggest you zero the screw by counting CW clicks.  Then return to your starting point and start making adjusments.  This way you can always return to the starting point if you mess up counting or turning the screw.  Sort of an insurance policy.

I have suggested this to others but an easier adjustment on the rack can be made using the BC.  It has a direct impact on the rack and is adjusted by shims versus screw turns.

What exactly are you trying to do?

[wwheeler]

Thanks for the input.

I am trying to fine tune my mixture at mid to high speed. On the highway, the engine accelerates OK, but seems like it could be a bit better. I have gone through all of the normal tune up stuff and have a 123 distributor.

When I do the split linkage test, it seems good and the plugs look OK as well. I want to fine tune the mixture slightly lean or rich and see if the highway acceleration improves. Is the BC the easiest way to do that?

[jeffc280sl]

You're welcome.

Adjusting the BC is the easiest way to add or reduce fuel volume across all rpm ranges.  This what the rack screw does.  Put a piece of tape on the BC and loosen it 1/2 turn CCW.  This will add fuel to the mixture. Wedge a piece of hose against it to hold it steady.  Go for a test run.

[wwheeler]

Jeff,

Do you happen to know what the ID and OD dimensions of the BC shims need to be? I would like to make them up in advance so I can put them right on during testing.

Thanks.

[jeffc280sl]

id is 14mm and od is 19mm

[wwheeler]

Since my FIP was rebuilt recently, the BC was easy to loosen. I used a 3/4"(19mm) open end wrench and had to cut the closed end off so it would fit in the engine bay. It did have a quick effect on the mixture and a half of a turn gave me a good change and now will test drive. I am using a piece of rubber heater hose that is wedged between the BC and the WRD to hold the BC steady while I make adjustments as you suggested. I'll put the correct shims in later once I get it just right.

This is a whole lot easier than messing with the rack screw. Thanks for the tips Jeff!

[jeffc280sl]

you're welcome.  ADalton deserves credit for the idea.  He kindly passed this tuning idea to me.  Glad this is helping.

[Witt]

I tried to adjust the full range screw on my FIP tonight with no luck after I read all of the info regarding the adjustment.

I removed the socket head cap screw and seal ring from between the two solenoids with a 5mm Allen wrench. I used a long thin slotted screwdriver to try to find the internal screw. When I inserted the screwdriver about 1", I ran into something that was lightly sprung. I could not find the slotted screw so I pushed about 3/4"deeper, I then ran into something that had a much higher spring rate. I still could not find a slot in the screw here either. If I had to guess, this last spring felt like it was moving the rack. 

Is there some special screwdriver that needs to be used? Why can't I find the adjustment screw? When I do find it, does it have the same feel (click) as the idle mixture knob?

Thank you! 

......I run into the very same problem when I tried to adjust, lean out, the IP via that adjustment screw. After I removed the top solenoid I discovered that an upside down  L-shaped springloaded bracket is obstructing access to the screwhead. I had to fiddle with a thin screwdriver thru the solenoid access hole circumventing said bracket to reach the adjustment screw.....and nobody beliefed me .

CHEERS
WITT !     

[wwheeler]

Witt,

That is exactly what the first spring loaded obstacle felt like. A very lightly loaded flap as you described. I didn't want to take off the solenoid and explore, so I began messing with the BC. I definitely have more confidence adjusting with the BC. The adjusting screw is more vague and you can't really see what you are doing, especially with a pump that has double solenoids.

[Witt]

Hey,
Glad someone is agreeing with me.....nevertheless on the advise of a site member I adjusted my IP via the BC just as you did and all is well. My milage has improved greatly.

CHEERS !
WITT !